Not sure if your OE AC brackets will work but if it's helpful, I am running a 454 (Gen VI 7.4L)
Headers = Sanderson ceramic 3/4 length BBC headers for 67-87 Truck, patented leak-free flange design. I'm very satisfied with these headers. (
https://www.sandersonheaders.com/san...category_id=27)
AC brackets = Because I am running an aftermarket AC system from Old Air, I am using their AC/Alternator brackets. Depending if it's long or short water pump
(
https://www.oldairproducts.com/categ...parts/brackets)